public class UT_Entitlements_Settings {
    static testMethod void testEntitlementsSettings() {
        Entitlements_Settings__c es = new Entitlements_Settings__c( Case_Entitlements_Field_Id__c='00N' );
        insert es;
        system.assertEquals(1,[Select Count() From Entitlements_Settings__c],'Only one ES row is allowed');
    }
}